Exhaust connecting branch for turbines.



H. ZOELLY. EXHAUST CONNECTING BRANCH FOR TURBINES.

APPLICATION FILED MAR. 3. 1915.

1 ,Q? 6, 1 54. Patnted Aug. 20, 19180 fgwjwgv v W I Q till till

UNITED STATES PATENT QFFICE.

WEINRIUH ZGELIIY, 0F ZURICH, SWITZERLAND, ASSIGNOR 'I'O AKTIENGESELLSGHAFT DEB MASCHINENFABRIKEN ESGHER WYSS & CIR, 0F ZURICH, SWITZERLAND.

EXHAUST CONNECTING: BRANCH FOR TURBINES.

Specification of Letters Patent. Patented Aug. 20, 1918.

Application filed March 3, 1915. Serial no. 11,845.

To all whom it may concern:

Be it known that 1, Hammer: ZOELLY, a citizen of the Republic of Switzerland, residing at Zurich, Switzerland, have invented new and useful Improvements in Exhaust, Connecting Branches for Axial-Flow Steam or Gas Turbines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to letters .or figures of reference marked thereon, which form a part of this specification. v

This invention relates to improvements in exhaust connecting branches for, axial flow steam or gas turbines. The exhaust connectin branch is so formed that the work-' ing fluid flowing from the outlet ofxthe last rotor wheel toward the outlet opening of the exhaust connecting branch passes, owing to the provision of guide-walls in said branch, through a continuously widening path, whereby the working fluid, whose velocity is continuously decreasing, while its pressure is {continuously increasing, is diverted from the axial direction into a direction substantially at right angles to the turbine axis. The guide-walls fitted in the branch may form substantially a hornshaped body or casing tapered toward the branch outlet and having a curved middle line. Between the wall of the branch and said built-in guide casing there may be provided uniformly curved guide vanes divert ing the working fluid from the outlet of the rotor wheel along the nearest toward the branch outlet.

in an exhaust connecting branch provided with such an arrangement the cross section of the diverted middle or center stream of possible path 'the working fluid, having a relatively high this manner it is possible that the prescare at the worwng fluid is lower at the point where said fluid flows into the branch than at the point where it leaves this branch. At the same time the working fluid flowing substantially in an axial direction at the point where it leaves the rotor wheel is diverted into a direction substantially at right angles to the turbine axis. The attainment of these aims is possible to a very high degree through the employment of special guide vanes, which, gradually and in a manner avoidin shocks-and eddies, divert the Working fluld leavin the last rotor wheel by the nearest possi le path toward the branch outlet.

The invention may be applied'to steam or gas turbines having a horizontal or vertical shaft and having exhaust connecting branches, whose central axis lies in a vertical, horizontal or any other intermediate direction.

One method of carrying the invention into efi'ect is shown by way of-example in the accompanying drawing in which:

Figure 1 is a vertical longitudinal section throughthe exhaust connecting branch of a steam turbine having a horizontal axis and Fig. 2 a cross section on the line II of Fig. 1 seen in the direction of the arrow A. Behind the last rotor Wheel 1 of the turblue is arranged the exhaust connecting branch, the casing 2 of which has a horizontally directed inlet and a vertical outlet directed downward. Inside the casing 2 there is fitted the horn-shaped guide casing 3 having, immediately behind the last rotor wheel 1, z. a, at a?) '(Fig. 1) circular cross section. The outer diameter D of this cross section is somewhat smaller than the diame-- ter of the root circle of the moving blades on the rotor wheel 1. As seen in Fig. 1, the cross section of the guide casing 3 has substantially such a shape, that its middle line conforms to the curved middle line of the exhaust connecting branch 2. Moreover, the cross section of the guide casing is continuously diminishing toward the outlet opening c-d of the branch 2. Further, as seen in Fig. 2, the width D of said ide casing 3 decreases gradually toward t e outlet opening III-c of the branch 2. The entire guide casing has, therefore, substantially the shape of a curved horn, the curved central axis of which deviates only slightly from the curved central axis of the exhaust connecting branch.

In order to divert in the best possible manner the layers of steam flowing out of ing with the built-in guide casing.

the rotor wheel on both sides of the guide casing (as seen in Fig. 2) from their initial direction, which is substantially parallel to the turbine axis, to a direction at right angles to the branch outlet, 71. e. at right angles to the lines fg of Fig. 1 and hi of Fig. 2, respectively, guide vanes 4 to 9 are provided between the casing wall of the exhaust connecting branch 2 and the guide casing 3, the meridian lines of these guide vanes coinciding with the path, which it is intended that the working fluid should follow. These guide vanes and the branch may form one casting or the said vanes may be welded to the wall of this branch 2' or to the guide casing or to both these pieces, or they may be connected by means of screws, rivets or the. like to the one or the other or to both .of the said main pieces. Moreover, middle ribs 10 and 11 may connect the branch (i eise edges of the deflecting walls 4 to 9 and the middle rib 10, which are placed in the path of movement of the working fluid have to be arranged at such a distance (8 in Fig. 1) from the last rotor wheel, that the working fluid is prevented-from impinging directly against these walls.

As in the case of the exhaust connecting branch also the guide casing may be subdivided in the horizontal plane. Its cross section need not form a wholly closed body. Thus, apart of the closed body shown on the drawing may be dispensed with particularly in the upper portion.

What I wish to claim is:

1. An exhaust connecting branch for axial flow steam or gas turbines, comprising a casing open at bothtends and guide-wallsbuilt-in in said casing, said guide-walls being so formed and so arranged within said casing, that theworking fluid flowing from the outlet of the last rotor wheel toward the outlet of the branch passes through a continuously widening path, whereby the said working fluid whose velocity is continuously decreasing while its pressure is continuously increasing, is diverted from the axial direction into a direction substantially at right angles to the axis of the turbine.

2. An exhaust connecting branch for axial flow steam or gas turbines, comprising an outer casing having an inlet opening lying in a plane at right angles to the turbine axis and an outlet opening lying 'in a plane at right angles to the plane of the inlet opening and a guide casing built-in in said outer casing, said guide casing forming substantially a horn-shaped body tapered to a point toward the branch outlet and having a curved axis.

3. An exhaust connecting branch for axial flow steam or gas turbines, comprising an outer casing having an inlet opening lying in a plane at right angles to the turbine axis and an outlet opening lying in a plane at right angles to the-plane of the inlet opening, a guide casing built-in in said outer casing, said guide casing forming substantially a horn-shaped body tapered to a point toward the branch outlet and having a curved axis, and continuously curved guide vanes arranged between the outer casing and the guide casing, whereby the said guide vanes divert the working fluid leaving the rotor wheel along the nearest possible path toward the outlet opening of the branch.

4. An exhaust connecting branch for axial flow steam or gas turbines, comprising an outer casingprovided with an inlet and outlet opening for the working fluid and a horn-shaped built-in body in said outer casing and tapered to a point toward the branch outlet and having a curved axis, said body being connected by means of ribs to the outer casing, a continuous space being provided between the outer casing and the built-in body, whereby the annular cross sections of said space continuously increase toward the outlet opening of the branch.

5. An exhaust connecting branch for axial flow steam or gas turbines, comprising an outer casing provided with an inlet and outlet openin for the working fluid, a hornsha ed built-in body in said outer casing an tapered to a point toward the branch outlet and having a curved axis, said body being connected by means of'ribs to the outer casing and a continuous space being provided between the outer casing and the built-in body, whereby the annular crosssections, at right angles to the axis of thebuilt-in body, of said space continuously increase toward the outlet of the branch, and continuously curvin guide vanes arranged in said space near t e inlet opening of the outer casing, which guide "anes divert the working fluid leaving the rotor wheel, along the nearest possible path toward the outlet opening of the branch.

6. Exhaust connection for axial flow steam and gas turbines, comprising a casing and guide-means therein cooperating with said casing to direct exhaust motive fluid in a continuously expanding path constantly changing in direction from the inlet end to the outlet end of said casing and said paths substantially parallel to the longitudinal middle plane through said casing and means.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribin witnesses.

. HEINR OH ZOELLY.

Witnesses:

ERNST FISCHER, CARL Gunman. 

